When you expose one frame of film twice, the light from both exposures adds up. To keep the result from looking overexposed, reduce each exposure so the total matches the reading for a single shot. For two exposures, that is typically one stop less light for each, though your scene and taste will shift this.
The Basic Idea
Film responds to the total amount of light it receives. Take a normal meter reading, then divide that light between the two exposures.
- Two equal exposures: underexpose each by one stop from the metered value.
- Three exposures: underexpose each by about one and a half stops.
- Four exposures: underexpose each by about two stops.
These are general guides. Dense film such as color negative stock tolerates some overexposure, while slide film is far less forgiving, so adjust to your material.
Step by Step Metering
- Decide whether the shot is a bright and a dark scene, or two similar scenes.
- Meter the first subject and note the suggested exposure.
- Reduce exposure by the adjustment above. You can set the film speed dial to a higher ISO, such as doubling it, which tells the meter to give less light.
- Make the first exposure with the camera set up for a double exposure, or use the multiple exposure mode if the camera has one.
- Meter the second subject separately, apply the same reduction, and make the second exposure.
- Record both frames in a notebook so you can learn from the results.
Plan Where Light and Shadow Fall
Where bright areas of one image meet dark areas of the other decides what shows. A dark area in the first frame leaves the film mostly unexposed, which lets the second image show through clearly.
| First image | Second image | Result |
|---|---|---|
| Dark silhouette on bright sky | Textured subject such as leaves | Texture fills the silhouette |
| Bright subject on dark backdrop | Any detailed scene | Second image appears mostly in dark areas |
| Two bright scenes | Same | Risk of washed highlights, so cut exposure more |
- Bracket by shooting several versions with different reductions on the same roll.
- Use a light meter set to spot mode for more control over the key areas.
- Keep in mind that the exposure for dark subjects should not drop too far, or detail will be lost in shadow.
FAQ
Can I double expose with a camera that lacks a multiple exposure feature?
Often yes. Some cameras let you cock the shutter without advancing film, and others need a different workaround. Check the manual for your model, and consider making a test roll.
Should I use a tripod?
It helps if you want exact alignment between frames. For loose, abstract results, handheld shooting is fine.
The Short Version
Meter for a single shot, then cut each exposure so the total light matches that reading, about one stop less each for two exposures. Plan where bright and dark areas overlap, bracket a few versions, and keep notes to refine your method.
